Meaning A boy's name of Gaelic origin, it means "Slender; Fair." Origin of Keillan Gaelic , Irish +-100%Zoom level changed to 1 Popular Middle Names Patrick Pronunciation 🔊 Listen Keillan Similar Names Kaelan Kaelin Kalen Kelden Kelle Keilan Keelan Keeland Kyle Findley Year by Year Popularity of Keillan